Chen Ji
DOI Number: N/A
Conference number: IFASD-2024-179
Launch vehicles may experience transonic buffeting during atmospheric ascent. Usually, fluctuation pressure wind tunnel test with rigid model is performed to assess the buffeting
loads. However, for the configurations prone to buffeting, such as the large-diameter fairing with a hammerhead nose shape, it is recommended to use an elastic model to study their buffeting response and evaluate potential hazards. In this paper, a set of elastic models with same structural dynamic characteristics and different diameters of fairings were investigated for their transonic buffeting behaviours. The configurations with different fairing-core diameter ratios are 1.55, 1.60, and 1.73, respectively. The aerodynamic damping and buffeting load response of the configurations were obtained by conducting aerodynamic damping tests and buffeting load response tests in transonic wind tunnel. The aerodynamic damping test results showed that the aerodynamic damping of the first free-free bending mode of the models with diameter ratio of 1.55 to 1.73 are positive at certain Mach numbers and Angle-of-Attack. However, solely from the perspective of aerodynamic damping, it is not sufficient to evaluate the buffeting behaviours of the larger diameter ratio fairings. The buffeting load response test results evident that with the increase in diameter ratio, the structural dynamic load response, in terms of both response amplitude and
the Mach number range of significant amplitude, increases, especially for the 1.73 diameter ratio case. This implies that with larger diameter ratios, the buffeting response amplitude becomes more severe, and the duration of significant response increases.